Ch40zzC0d3r's idea:
I thought about it ,but it won't work. If you went to a direction in the real world ,you will go to the same direction in the mirror no matter you set CULL_CW for the view or not
environment mapping:
Actually, I don't have very good experience with shaders
. I used the floor reflection ,but it didn't work. I am sure there is something missing.